This invention relates to a fuel cell and more particularly to a fuel cell suitable for cells using molten carbonate as an electrolyte.
A fuel cell has an electrolyte body between a pair of electrodes, i.e. anode and cathode, and the electrolyte body comprises a porous electrolyte-retainable material and an electrolyte retained in the pores of the porous electrolyte-retainable material. A practical fuel cell comprises a plurality of unit cells stacked one upon another, and the conventional means of successively stacking anodes, electrolyte bodies, cathodes and cell frames as cell constituent members one upon another has the following problems:
(1) It is difficult to fabricate an electrolyte body with a good flatness, and is liable to have a curving or waving. Thus, stacking is hard to carry out. For example, when the cell constituent members are stacked one upon another and secured together by bolts, etc., the electrolyte bodies are cracked or damaged. A good contact cannot be obtained between the electrodes and the electrolyte bodies, or between the cell frames and the electrolyte bodies. When no good contact is obtained between the electrodes and the electrolyte bodies, a good three-phase boundary (field of electrode reaction formed in the presence of electrode catalyst, electrolyte solution and fuel or oxidizing agent) will be hard to maintain, resulting in lowering of cell performance. When no good contact is obtained between the cell frames and the electrolyte bodies, a wet sealing between the electrolyte bodies and the cell frames by an electrolyte solution (prevention of gas leakage) will be not satisfactory and it will be difficult to prevent a gas leakage from the wet sealing.
(2) The cell constituent members must be stacked one by one and thus the stacking work will be complicated and also will not always be satisfactory from the viewpoint of assembling precision. Careful stacking work is required for complete sealing of manifolds or for provision of a complete gas passage against a possible failure in alignment of the cell constituent members, and also for handling of each of the cell constituent members, particularly electrolyte body.